The present invention relates to a brake control device of a brake system which performs an interlocking brake control of a front-wheel-side brake and a rear-wheel-side brake, and an anti-lock brake control.
Conventionally, there has been known a brake control device of a brake system which performs an anti-lock brake control using an anti-lock brake system (ABS) by controlling a fluid pressure of a brake fluid supplied to a braking part by a hydraulic circuit. In this type of brake control device, a pressure of a brake fluid in the hydraulic circuit is increased by driving an electrically-operated pump provided to the hydraulic circuit. Usually, when a supply voltage supplied to the electrically-operated pump is lowered, discharge capacity of the electrically-operated pump is lowered. When a discharge amount of brake fluid from the electrically-operated pump cannot be maintained at an amount sufficient for performing an anti-lock brake control because of such lowering of discharge capacity of the electrically-operated pump, an overstep-in of a brake lever or a brake pedal takes place. Accordingly, an accumulator of the hydraulic circuit is filled with a brake fluid and hence, it becomes difficult to properly perform an anti-lock brake control. In view of the above, in the conventional brake control device, when a voltage value is lowered to a predetermined value or below, an anti-lock brake control is stopped.
Further, there has been proposed a front and rear wheel interlocking brake system (CBS) which automatically properly controls a balance between a braking force applied to a front wheel and a braking force applied to a rear wheel so as to take a proper balance between a braking force of a front-wheel-side brake and a braking force of a rear-wheel-side brake (see patent documents 1, 2 and 3, for example). This front and rear wheel interlocking brake system includes an ABS, and further includes a front-wheel-side brake circuit and a rear-wheel-side brake circuit, wherein both brake circuits are interlockingly operated in response to a brake operation of a user so that a balance between the braking force applied to the front wheel and the braking force applied to the rear wheel is automatically properly controlled.